*{
    padding: 0;
    margin: 0;
    list-style: none;
}
.big{
    width: 550px;
    height: 50px;
    margin: auto;
}
.big ul li{
    float: left;
    width: 40px;
    height: 40px;
    border: solid 1px black;
    text-align: center;
    line-height: 40px;
    margin-left: 5px;
    font-size: 12px;
}